Hi, try: 3-bar menu > Options > Privacy & Security, then under Content Blocking, remove all blocks; also under Permissions, deselect any block on Pop-up windows.

Now reload the site. If that works, should you wish, you can make an exception for the site.

If you are using an ad-blocker try disabling it, or turn it off on that site, then reload the page. (3-bar menu > Add-ons > Extensions).

If you have other extensions, try disabling them, or hold down the Shift key when you start Firefox to start in Safe Mode. More - Diagnose Firefox issues using Troubleshoot Mode.

If your question is resolved by this or another answer, please help other users by marking the best reply as Solved. Thank you!

I tried the advice in the first paragraph but that did not resolve it. Disabling the Ad Blocker did! Odd as it has been installed for yonks without any problem.

Thank you for your help.

Regards

Odder still - when I re-enabled the Ad Blocker PayPal still worked. Must have been a gremlin in the works as all the settings are back as they were and it is now fine.

I'm having the same problem and nothing is working. The only thing that worked was to make my paypal purchase using Chrome. No problems there.

You need to add www.paypal.com or whatever paypal site you use to the Exceptions under Block Pop-Ups in Privacy & Security.

Click the three little lines in the top right hand corner and select Options. On the left hand side click Privacy & Security. Scroll down to the Block Pop-Ups check box. Click the Exceptions button and type www.paypal.com or www.paypal.your country suffix

Once I disabled the Amazon Assistant for Firefox extension add on PayPal worked fine. Try disabling one extension at a time it could be as simple as that.

I just fixed it by going into privacy and security>manage data and deleted all cookies from ebay and paypal. after I signed back into ebay and checked out paypal worked as usual.